Eisai, Biogen start delayed subcutaneous Leqembi filing

Eisai, Biogen start delayed subcutaneous Leqembi filing

Eisai and Biogen have filed a rolling biologics license application in the US for a subcutaneous formulation of Alzheimer’s disease therapy Leqembi that was delayed by the FDA on procedural grounds.

The rolling submission – which allows supportive data to be filed in stages – is for a once-weekly autoinjector formulation of Leqembi (lecanemab) that would do away with the need for regular clinic visits needed for the current intravenous version of the drug. It would be used after a biweekly IV initial induction course, the duration of which remains under discussion with the FDA.

It is part of a concerted effort by the two pharma groups to simplify the dosing regimen for the amyloid-busting drug and try to accelerate sales growth, which remains fairly sluggish - albeit with signs of a modest pickup in the first quarter of this year.

Clinical data has suggested that six months of weekly dosing of the subcutaneous formulation was superior to the approved biweekly infusions of Leqembi at removing amyloid plaques from the brains of Alzheimer’s patients.

A few weeks ago, Eisai and Biogen also filed to extend the label for Leqembi to include a maintenance dosing regimen that would reduce the number of intravenous infusions needed to prevent amyloid accumulation in the brain to one per month.

The partners had planned to file a rolling application for the subcutaneous formulation in March under the existing fast-track and breakthrough therapy designations for intravenous Leqembi.

However, that plan was scuppered when the FDA said it would need fast-track status that was specific to the subcutaneous form, which was filed shortly afterwards, but kicked off a 60-day review period.

Leqembi is currently approved in the US, Japan, and China for Alzheimer’s patients with mild cognitive impairment or mild dementia, and is under regulatory review in the EU and other markets, including GB and Canada.

The drug is designed to target the most neurotoxic protofibril form of amyloid, clearing it from the brain. Protofibrils can continue to cause damage to neurons even after the deposits have been cleared, however, and maintenance dosing is designed to maintain Leqembi’s benefits.

Studies have suggested that amyloid plaques start to reaccumulate after treatment with anti-amyloid stops – estimates are by around 3% to 4% per year – so, hypothetically at least, there could be a benefit from extended use of the drug.

Biogen said last month that in-market sales of Leqembi were $19 million in the first quarter, up from $10 million for last year as a whole and ahead of analyst expectations, with a 2.5-fold increase in the number of patients currently on treatment with the anti-amyloid drug. 

Take-up has been held back by a requirement for diagnostic testing and monitoring for side effects, access to clinical capacity for the twice-monthly infusions needed with treatment, and lingering scepticism about its benefits among physicians.

Today, however, Eisai updated its financial guidance for the drug, saying it expects prescribing to ramp up this fiscal year to reach more than $360 million.